The MPA 21 is a 2-channel, multiplexed photoelectric amplifier, which is to be used in conjunction with 2 sets of remote transmitters LT and receivers LR, from the series 100, 110 and 120.

The 2 channels operate independently of each other with their own set of remote transmitter and receiver. The multiplexing function ensures that optical cross talk between channels is prevented.

The series offers a choice between 2 individual relays or 2 individual NPN/PNP transistor outputs, with or without an adjustable 0-3 sec on/off time delay.

This amplifier series offers manual sensitivity adjustment for each individual channel via integral potentiometers located on the front panel of the amplifier. Light or dark function and long or short range are switch selectable for each individual channel.